Repetition-action for pianos.



L. OHARPIAT. REPETITION ACTION FOR PIANOS. APPLIOATIONAIILED JAN. 29, 1908.

Patented Nov. 17, 1908.

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L. OHARPIAT. REPETITION ACTION FOR PIANOS.

APPLICATION FILED JAN.29,190B.

Patented Nov. 17, 1908.

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I WWW 4V WM I L. UHARPIAT. REPETITION ACTION FOR PIANOS. APPLICATION FILED JAN. 29, 1908.

Patented Nov. 17, 1908.

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L. OHARPIAT. REPETITION ACTION FOR PIANOS. APPLICATION FILED JAN 29 1908 @NXE @W W C LOUIS CHARPIAT, OF NEW YORK, N. Y.

REPETITION-AGTION FOR PIANOS.

Specification of Letters Patent.

Patented Nov. 17, 1908.

Application filed January 29, 1908. Serial No. 413,247.

To all whom it may concern:

Be it known that I, LOUIS CHARPIAT, a citizen of the Republic of France, and a resident of the borough of Bronx, city, county, and State of New York, have invented certain new and useful Improvements in Repetition-Actions for Pianos, of which the following is a specification.

My invention relates to piano actions and comprises a repetition action for grand pianos which is an improvement on that shown in my United States Patent No. 717,349, granted December 30, 1902. In my said prior patent I have shown an apparatus in which the old form of repetition lever is dispensed with and a repetition spring does the work formerly done by the repetition lever and spring.

My present invention comprises an improved form and arrangement of such repetition spring and other detailed improve ments which will be hereinafter pointed out.

The best form of apparatus at present known to me embodying my invention is illustrated in the accompanying drawings in which,

Figure l is a side elevation of a part of the action for one key with parts broken away, the supporting rails and base being shown in cross section and the hammer in its lowest position. Fig. 2 is a similar view with the hammer at mid stroke. Fig. 3 is a similar view with the parts in the position assumed when the hammer hits the piano string. Fig. 4 is a diagrammatic view showing the operation of my improved form of jack. Fig. 5 is a detail perspective view of the repetition spring, and Fig. 6 shows a modification. Fig. 7 is an enlarged detail of one of the adjusting screws.

Throughout the drawings like reference figures indicate like parts.

As shown in the drawings, the mechanism comprises the following parts: the jack-can rying arm 1, to which the ack 2 is pivoted at 2,; the hammer butt 3 comprising the shank 41 set in the socket 42 of the socketpiece 43 upon which latter the jack operates through the medium of the nose 4 formed by strips of cloth and leather bent nearly at right angles and seated in the-socket piece around the end of the shank. The hammer butt oscillates about the center 5, formed by the pivot bearing on a flange of the hammer butt carrying rail 15. The drop screw 6 is set in this flange of the hammer butt carrying rail, and cooperates with the cushion 6, carried by the free end of the repetition spring 7, which spring is pivoted at 9 on the jack carrying arm 1, and has its tension adjustable by the adjusting screw 8 which is provided with a left hand thread.

The usual hammer is shown at 13, and 12 is the key, balanced at 26 on the key bottom 27. The key moves the action by means of the capstan screw 29 which engages the heel 28 on the jack-carrying arm. The jackcarrying arm has the usual jack stop 11 with which the jack regulating button 24, carried by the jack cooperates. The jack is normally held with the button against the stop by the jack spring 18, which is confined between the heel 28 and the face 19 of the inner end of the jack arm 22. This face 19 is in a plane passing through the axis of the pivot 2,. The jack stop 11 is bifurcated at its upper end 10, to form a guide for the repetition spring and it also carries the screw 20 which forms an adjustable stop for the repetition spring. The jack-carrying arm is pivoted at 14 to the rail 23. The set-off button 21 is carried by the set-01f button rail 16, by means of the adjustable screw threaded set-off pin 17. The set-off button cooperates with the outer end of the jack arm 22. The hammer 13 is stopped in its lowest position by the hammer stop rail 31, but normally the hammer rests slightly above the rail 31, as shown in Fig. 1. The repetition spring 7 has a flattened portion 30 cooperating with the hammer-butt nose 4, and the semicircular curved portion 34 cooperating with adjusting screw 20. The jack 2 is bifurcated at its upper end as indicated at 33, to clear the repetition spring.

32 is the piano string.

The jack 2 has its inner face cut away at the end on a line /z. passing through the jack pivot 2 The hammer check or back check is shown at 50.

lVhen the outer end of the key 12 is de pressed, the inner end of course rises, carrying with it the capstan-screw 29, which presses against the heel 28 on the jack-carrying arm and rotates said jack-carrying arm about its center 14. This causes the jack 2 to rise and by the pressure of the end of said jack upon the felt nose 4 the hammer-butt 3 is thrown up, and with it the hammer 13, which strikes the piano-string 32. After the key and action have moved in the abovedescribed manner through nearly the whole distance rendered possible by the permissible movement of the key the set-off arm 22 comes in contact with the set-off button 21,

and further motion of the action forces the jack 2 out from under the nose at, and the momentum of the hammercarries the ham-' mer through the remaining distance to strike the blow on the piano-wire. bounding of the hammer its backward mo tion beyond a certain point is checked by the back check 50 and itrests on the repetition spring 7, which is slightly depressed by the rebound of the hammer and comes into play as soon as the hammer is released from the check, and lifts the hammer slightly and holds it up so that the ack may return under the nose 4. The use of the form of nose t set into the hammer-butt socket piece near the central line of the hammer butt, enables me to arrange the center 1ft of the jackcarrying arm pivot and the pivot 5 of the hammer-butt in line or approximately in line with the medial position of the contact pointbetween the jack face and the hammer butt nose 4:, without shortening up the jack-carrying arm. This reduces the relative rubbing motion between the jack and the nose to the minimum, and not only prolongs the life of the parts but reduces friction to the minimum during the operation of striking a note. This arrangement is made clear by the dotted lines in Figs. 1, 2 and 3. In mid position of the hammer shown in Fig. 2, the line aZ) connecting centers 5 and 1% passes through the point of contact between the jack face and the nose t and is practically tangent to the contact faces. In the lower position of the hammer shown in Fig. 1, this point of contact is only a slight distance below line cZ and in the uppermost shown in Fig. 3, it is an equal distance above line a-b. The amount of rubbing travel between the surfaces of jack and nose is represented by the hardly perceptible distances between the dotted arcs w and y, along the line of contact between jack and nose in Figs. 1 and 3. Similarly the pivot 9 of repetition spring 7 being in or approximately in dotted line 0 (Z passing through pivot 14: and point of contact between drop screw 6 and cushion 6,, in Fig. 3, there is little or no rubbing of the parts 6 and 6., on one another during the Upon the re back under the hammer-butt nose more easily 2,, also produces a direct and frictionless compression of this spring, preventing its displacement, giving it full power of action and producing a prompt return of the ack under the hammer-butt nose. All the adjusting screws are so arranged as to be reached by a screw driver from above the action and are consequently easily accessible and adjustable without disturbing the other parts. The left handed screw 8 permits the repetition spring to be tightened by a right hand turning of the screw driver which is the natural move ment for a mechanic in setting up a spring adjustment. The repetition spring is efficiently guided by the bifurcated end 10 of the jack stop 11. The curved portion of the spring enables the adjustable screw stop 20 to be in line with the repetition spring 7 and exert its restraining action evenly thereon.

Of course certain of the improvements herein described may be used without employing others, but the best results from my invention are obtained from the combined action of all the parts as described, or their mechanical equivalents.

In Fig. (3 I have shown a further modification of the ordinary action in which the mathematical principles for the reduction of rubbing friction between the parts are applied to the connection between the piano key and the jack-carrying arm. As shown, the capstan screw 29 is put in an inclined position so that it is at right angles to dotted line Zm which passes through the key pivot 26 and is tangent to the curved head of the capstan screw. In the same way, the bearing face of the heel 28 of the jack carrying arm is inclined so as to be approximately tangential to the line Zm, as shown in Fig. 6

so that when the ey 12 is half way depressed, the surface of 28 will be exactly tangential to the line Zn which passes through centers 26 and 14-. The dotted line Z0 indicates the upper limit of travel of the surface of the capstan screw and the angles at Z a and a Z 0 are approximately equal. It is evident that this arrangement of the rubbing surfaces will reduce the friction to the minimum amount, and also reduce the amount of rubbing travel between the capstan-screw and jack carrying arm heel to the minimum, the heel moving only a slight distance to the right of Fig. 6 over the top of the capstan screw during its motion from line Zm to line Zn, and an equally short distance to the left during travel from position Z-n to position Z-0.

Having, therefore, described my invention, I claim:

1. A piano action, comprising the combination of the hammer butt, the jack and jackcarrying arm, the straight line connecting the hammer butt pivot with the ack carrying arm pivot touching and being approximately tangent to the contact faces of the jack and the hammer-butt nose at mid stroke of the hammer.

2. A piano action, comprising the combination of the hammer butt, the jack and jack carrying arm, the straight line connecting the hammer butt pivot with the jack carrying arm pivot touching and being approximately tangent to the contact faces of the jack and the hammer-butt nose at mid stroke of the hammer, said hammer-butt nose comprising a wearing strip bent approximately at right angles and seated in the hammer butt.

A piano action comprising the combination of the pivoted hammer butt socket piece, the hammer shank set in said socket piece, and the nose formed on said socket piece and comprising a wearing strip bent approximately at right angles and seated in the socket piece, around the end of the shank.

'-1l-. A piano action, comprising the combi nation of the hammer butt, the ack carrying arm, and ack pivoted thereto, the working face of said jack engaging the hammer butt being at right angles to a line drawn from the jack pivot to the inner corner of the jack face.

5. A piano action, comprising the combination of the jack carrying arm, the jack pivoted in the end thereof, an arm fastened to the lower end of the jack, the set-off button with which one end of the arm cooperates, and a spiral spring confined between the other end of the arm and the jack carrying arm, the face of the jack arm against which said spring presses being in a plane passing through the axis of the jack pivot.

G. A piano action, comprising the combination of the pivoted jack carrying arm, the

repetition spring pivoted on said arm, and l the stop for the outer end of said spring, the pivot of the spring being in a straight line connecting the pivot of the jack carrying arm with the point of contact of the stop and spring whenever such contact occurs.

7. The combination with a pivoted piano key of a piano action comprising a pivoted jackcarrying arm, the key and jack carrying arm having cooperative projections normally in contact, the contact surfaces at midstroke of the key being tangential to the line joining the pivotal centers of the key and jack carrying arm.

8. The combination with a piano action of a pivoted piano key and capstan screw set therein at right angles to a line drawn through the key pivot tangential to the bearing surface of the screw head.

Signed at New York, N. Y. this 23rd day of January 1908.

LOUIS CHARPIAT. Witnesses A. PARKER SMITH, M. G. CRAWFORD. 

